Method for transporting magnetic objects

ABSTRACT

A magnetic transport system (8) has at least one magnetic transport roller (20) mounted to a frame (10) for conveying a ferromagnetic web (12). The transport roller (20) has a magnetic core (22), a first bonding layer (24) at least partially surrounding and bonded to the core (22), a first layer (26) at least partially surrounding and bonded to the first bonding layer (24), a second bonding layer 28 for bonding second layer 30 to the core (20). Second layer (30) comprises a wear and abrasion resistant material. Further, a ferromagnetic web (12) is arranged for movement along the magnetic transport roller (20) for transporting materials thereon.

FIELD OF THE INVENTION

The invention relates to the transportation of magnetic parts andmaterials, more particularly, the invention concerns a method fortransporting magnetic objects on a ferromagnetic web.

BACKGROUND OF THE INVENTION

Transport systems are used extensively in manufacturing processes totransport objects, more specifically, ferromagnetic objects, from onestation to the next station. In numerous manufacturing processes, thetransport system is exposed to abrasive or corrosive environments. Forinstance, in electroplating, painting and encapsulation of magnetspretreatment of the magnets such as cleaning, etching of the surfaces ofthese objects employing chemicals and abrasive particles is undertaken.It is imperative that during these pretreatment processes the magnetictransport system is not damaged by corrosion as well as by wear andabrasion encountered during the pretreatment of the magnets. Suchtransport system degrades when they are exposed to harsh chemicalmanufacturing environment. Furthermore, components of these transportsystems must be wear and abrasion resistant so that the transportedobjects are not damaged during their use. Therefore, there is a need todesign and manufacture a novel transport system which can effectivelytransport ferromagnetic components without damage either to thetransport system or to the components being transported. The subject ofthis disclosure is a wear, abrasion and corrosion resistant magnetictransport rollers and ferromagnetic transport webs for use in a harshand corrosive manufacturing environment.

The invention discloses a method for transporting magnetic objects usinga magnetic transport system that can effectively transport the magneticobjects through corrosive environments without damage either to thetransport system or to the objects being transported.

SUMMARY OF THE INVENTION

It is, therefore, an object of the invention to provide a method fortransporting magnetic materials in a corrosive environment.

It is another object of the invention to provide a method of transportwhich uses wear and abrasion resistant components.

Yet another object of the invention is to provide a method that employsa magnetic transport system that utilizes magnetic coupling between amagnetic roller and a ferromagnetic web for transporting magneticmaterials and objects.

It is a feature of the invention that the method includes the step ofproviding a magnetic roller in rotating contact with a ferromagnetic webthat has multiple layers including a corrosion resistant layer and awear and abrasion resistant layer surrounding a magnetic core.

To solve one or more of the problems above, there is provided a magnetictransport system having a frame and at least one transport rollermounted to the frame. The transport roller has a magnetic core and afirst bonding layer, at least partially surrounds and is bonded to thecore. Further, a first layer, comprising a corrosion resistant material,at least partially surrounds and is bonded to the first bonding layer ofthe roller. A second bonding layer is provided that at least partiallysurrounds and is bonded to the first layer. A second layer, comprising awear and abrasion resistant material, at least partially surrounds andis bonded to the second bonding layer. Moreover, a web comprising aferromagnetic material for magnetically adhering to the roller, isarranged for movement along the transport roller. At least a portion ofthe web is in rotating contact and is magnetically coupled to theroller. A drive means is provided for rotating the transport roller sothat the web moves along the roller under the influence of a magneticcouple.

It is, therefore, an advantageous effect of the present invention thatmaterials can be transported in a corrosive environment withoutdegradation of the transport system. It is a further advantage of theinvention that the transport system does not impart undesirable wear orabrasion to the materials being transported. Moreover, it is a furtheradvantage of the invention that materials can be transported in avariety of orientations without the concerns for adverse gravitationaleffects.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other objects, features and advantages of theinvention and the manner of attaining them will become more apparent andthe invention itself will be better understood by reference to thefollowing description of an embodiment of the invention taken inconjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic view of the web transport system of the presentinvention;

FIG. 2a is a perspective view of the transport roller with an attachedmotor drive;

FIG. 2b is a cross-sectional view taken along line 2a--2a of FIG. 2a;

FIG. 3 is perspective view of the magnetic roller and end shaft memberof the invention;

FIG. 4a is a perspective view of the web of the present invention; and,FIG. 4b is a cross-sectional view taken along line 4a--4a of FIG. 4a.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a schematic view is shown of a magnetic transportsystem 8 of the present invention. Broadly defined, transport system 8includes a rigid frame 10 (preferably metal) and at least one transportroller 20 having a permanent magnet core 22 (described fully below)mounted for rotation in the frame 10. A ferromagnetic web 12 (describedbelow) for transporting magnetic objects 16 is arranged for movementabout transport rollers 20 between a reservoir 14 and other upstreamstations (not shown) in proximity to transport system 8. Typicalmagnetic objects 16 transportable by the invention include, but are notlimited to, permanent magnets, and any object containing permanentmagnets.

As shown in FIG. 1, reservoir 14, preferably made from a rigid material,may have virtually any shape and size depending upon application.Generally, reservoir 14 may include an openable portion for accessingthe interior portion 15. A solution (S') may be added into reservoir 14with dispersed magnetic objects therein, such as colloidal size magneticparticulates, which require separation from the solution. In thisinstance, the solution (S') containing the particulates is exposed tothe ferromagnetic web 12 moving along transport roller 20 whichmagnetically separates them from the solution and then transport themupstream of the transport system 8 for independent treatment. Moreover,reservoir 14 may include an etching solution, such as hydrochloric acid,nitric acid and sodium hydroxide, for chemically etching the objectsprior to the objects 16 contacting and then being transported by the web12.

Referring to FIGS. 2a, 2b and 3, transport roller 20, driven by a motor60 (shown in FIG. 2a), includes a magnetic core 22 made from a permanentmagnet material. The core 22 is polarized with a plurality of radiallydisposed surface poles (denoted by N & S in FIG. 2b) of alternatingpolarity around its circumference. The web 12, which is a ferromagneticmultilayer web, comprises a ferromagnetic base layer 76 (shown in FIG.4b). The magnetically polarized objects 16 attract and adhere to theportion of web 12 that is in close proximity to the reservoir 14. Theportion of the web 12 that is in contact with the rollers 20 isattracted to the rollers 20 due to the force of attraction between thepermanent magnet cores 22 and the ferromagnetic base layer 76 of the web12 (shown in FIG. 4b). Thus, when the motor 60 (shown in FIG. 2a)rotates the rollers 20 (as indicated by rotation arrows 17), the web 12moves translationally by the transport rollers 20 (as indicated byarrows 18) and consequently transports the attached magneticallypolarized objects 16. The magnetically polarized objects 16 can beremoved from the web 12 at a desired location by use of an electromagnet(not shown) as is well known.

Referring to FIG. 2a, illustrated is a perspective, partially explodedview of the transport roller 20 with opposing end support members 50,52. Extending from each end support member 50, 52 is a respective shaft54, 56. Shafts 54, 56 are preferably shrunk fit onto a respective endsupport members 50, 52. Skilled artisans will appreciate that shafts 54,56 may also, for instance, be welded or bolted onto end support members50, 52. Roller 20 is attached to a motor 60 operably connected to rotorshaft 70 which is coupled at one of the end support members 50, 52 viaone of shafts 54, 56 for rotatably driving roller 20. The roller 20,driven by motor 60, can now rotate about its longitudinal axis in thedirection indicated by arrows 72, 74.

End support members 50, 52 are preferably made from American Iron andSteel Institute (AISI) 316 stainless steel which can be obtained fromany one of several well known suppliers.

In the preferred embodiment of the invention, shafts 54, 56 areelectroplated with Teflon™ impregnated nickel so as to reduce thecoefficient of friction.

Referring to FIG. 2b, roller 20 is illustrated in the cross sectionalview of FIG. 2a. Roller 20, as indicated above, comprises a magneticcore 22. Magnetic core 22 is made preferably from a non rare-earthpermanent magnet material such as aluminum-nickel-cobalt,barium-ferrite, copper-nickel-iron alloy, iron-cobalt-molybdenum alloy.Most preferred of the non rare-earth materials isaluminum-nickel-cobalt. In another embodiment of the invention, magneticcore 22 may be made of a rare-earth material such asneodymium-iron-boron, or samarium cobalt. In this instance, the mostpreferred material is neodymium-iron-boron manufactured by Magnaquench,Inc., Ind.

Referring again to FIG. 2b, in addition to magnetic core 22, roller 20comprises first and second layers 26, 30 surrounding the core 22. Layers26, 30 are preferably coated onto the core 22 using the techniquesdescribed below. According to our preferred embodiment, a first bondinglayer 24 is coated onto the core 22. First bonding layer 24 ispreferably comprised of copper or copper based alloys, chromium, gold,silver and combinations thereof. Most preferred is copper and itsalloys. Skilled artisans will appreciate that bonding layer 24 may beapplied to core 22 by using any of several conventional techniques. We,however, prefer depositing the first bonding layer 24 onto core 22 usingphysical vapor deposition (PVD), chemical vapor deposition (CVD), orsome electroless or electrolytic deposition process, each producingsubstantially the same result. Preferably, we deposited first bondinglayer 24 onto core 22 using an electrolytic deposition process. In thepreferred embodiment, first bonding layer 24 has a thickness in therange of about 50 to 200 Angstroms, preferably 100 Angstroms.

Referring once again to FIG. 2b, after the first bonding layer 24 isbonded to core 22, a first layer 26 comprising a corrosion resistantmaterial, is coated onto the first bonding layer 24. First layer 26comprises preferably a coating of electroplated nickel or electrolessnickel. The preferred method for depositing the first layer 26 ofcorrosion resistant material onto first bonding layer 24 is electrolessplating. The first bonding layer 24 functions to enhance the adhesion ofthe first layer 26 of corrosion resistant material to the core 22.Preferably, first layer 26 has a thickness between 0.1 mil and 1 mil,most preferred being 0.5 mil.

According to FIG. 2b, a second bonding layer 28 is coated onto firstlayer 26. Second bonding layer comprises alloys of nickel-aluminum,nickel-chromium, cobalt-chromium-aluminum or combinations thereof. Whilenumerous techniques may be used to deposit the second bonding layer 28,we prefer using a PVD or a plasma spraying method. Preferably, secondbonding layer 28 has a thickness in the range of about 1,000 to 10,000Angstroms, most preferred being 5,000 Angstroms.

Still referring to FIG. 2b, a second layer 30 comprising a wear andabrasion resistant material, is coated onto the second bonding layer 28.The second bonding layer 28 enhances the adhesion and minimizes theporosity of the second layer 30 by sealing pores (not shown) in thesecond layer 30. The preferred method for coating the second layer 30onto the second bonding layer 28 is by dipping the roller 20 insolutions of polyurethane or acrylic. Alternatively, the second layer 30may be spin or dip coated onto the second bonding layer 28 of roller 20in a solution of sol-gel comprising silicon dioxide or alumina. Yetanother acceptable technique for coating the second layer 30 onto thesecond bonding layer 28 is thermal or plasma spraying with a wear andabrasion resistant material such as chromium oxide, zirconium oxide,aluminum oxide, or composites of zirconia-alumina, or a combinationthereof.

Referring to FIGS. 2a and 3, a perspective view is shown of the roller20 having similarly tapered ends 32 and an end support member 50 mountedon either of the tapered ends 32. End support member 50 has an opening58 for receiving the tapered end 32 of roller 20. Preferably, endsupport member 50 is fixedly attached to a tapered end 32 of roller 20by shrink fitting or alternatively by press fitting.

Referring to FIG. 4a, a perspective is shown of the flexible magneticmultilayer web 12 which conveys magnetic objects 16. According to FIG.4b, web 12 is shown in cross-sectional view taken along line 4a--4a ofFIG. 4a. The web 12 comprises a ferromagnetic base layer 76. Theferromagnetic base layer 76 is flexible and comprises soft-magneticparticles embedded in a binder. Specifically, soft ferrities of thegeneral formula MOFe₂ O₃, where M is a divalent metal such as Mg, Mn, Nietc. are mixed in a binder system for manufacture of the base layer 76.The binder system essentially consists of organic materials such ascellulose acetate, Kevlar™ (manufactured by DuPont), nylon etc. Thedispersion of the soft magnetic particles in the binder system is knownin the art. The dispersed magnetic particles are formed into a webeither by knife coating or by extrusion or by any suitable means knownin the art such as tape casting.

In an alternate embodiment, the base layer 76 can also be formed on aflexible non-magnetic metal or alloy substrate such as austeniticstainless steel of 1 to 10 mil in thickness, Soft magnetic material canbe plasma or thermally sprayed on the flexible substrate using asuitable bond layer known in the art. Deposition of soft magneticmaterials can also be made on the flexible substrate through physicalvapor deposition (PVD), or chemical vapor deposition (CVD).

Referring again to FIG. 4b, in addition to the ferromagnetic base layer76, the web 12 comprises first and second web layers 86, 90 surroundingthe ferromagnetic base layer 76. Web layers 88, 90 are preferably coatedonto the ferromagnetic base layer 76 using the techniques describedbelow. According to our preferred embodiment, a first web bonding layer84 is coated onto the ferromagnetic base layer 76. The first web bondinglayer 84 is preferably comprised of copper or copper based alloys,chromium, gold, silver and combinations thereof. Most preferred iscopper and its alloys. Skilled artisans will appreciate that the firstweb bonding layer 84 may be applied to ferromagnetic base layer 76 byusing any of several conventional techniques. We, however, preferdepositing the first web bonding layer 84 onto ferromagnetic base layer76 using physical vapor deposition (PVD), chemical vapor deposition(CVD), or some electroless or electrolytic deposition process, eachproducing substantially the same result. Preferably, we deposited thefirst web bonding layer 84 onto the ferromagnetic base layer 76 using anelectrolytic deposition process. In the preferred embodiment, first webbonding layer 84 has a thickness in the range of about 50 to 200Angstroms, preferably 100 Angstroms.

Referring once again to FIG. 4b, after the first web bonding layer 84 isbonded to the ferromagnetic base layer 76, a first web layer 86comprising a corrosion resistant material, is coated onto the first webbonding layer 84. The first web layer 86 comprises preferably a coatingof electroplated nickel or electroless nickel. The preferred method fordepositing the first web layer 86 of corrosion resistant material ontothe first web bonding layer 84 is electroless plating. The first webbonding layer 84 functions to enhance the adhesion of the first weblayer 86 of corrosion resistant material to the ferromagnetic base layer76. Preferably, the first web layer 86 has a thickness between 0.1 miland 1 mil, most preferred being 0.5 mil.

According to FIG. 4b, a second web bonding layer 88 is coated onto firstweb layer 86. The second web bonding layer 88 comprises alloys ofnickel-aluminum, nickel-chromium, cobalt-chromium-aluminum orcombinations thereof. While numerous techniques may be used to depositthe second web bonding layer 88, we prefer using a PVD or a plasmaspraying method. Preferably, the second web bonding layer 88 has athickness in the range of about 1,000 to 10,000 Angstroms, mostpreferred being 5,000 Angstroms.

Still referring to FIG. 4b, a second web layer 90 comprising a wear andabrasion resistant material, is coated onto the second web bonding layer88. The second web bonding layer 88 enhances the adhesion and minimizesthe porosity of the second web layer 90 by sealing pores (not shown) inthe second web layer 90. The preferred method for coating the second weblayer 90 onto the second web bonding layer 88 is by dipping the web 12in solutions of polyurethane or acrylic. Alternatively, the second weblayer 90 may be spin or dip coated onto the second bonding layer 88 ofthe web 12 in a solution of sol-gel comprising silicon dioxide oralumina. Yet another acceptable technique for coating the second weblayer 90 onto the second web bonding layer 88 is thermal or plasmaspraying with a wear and abrasion resistant material such as chromiumoxide, zirconium oxide, aluminum oxide or composites ofzirconia-alumina, or a combination thereof.

While the invention has been described with a certain degree ofparticularity, it is manifest that many changes may be made in thedetails of the construction and the arrangement of the componentswithout departing from the spirit and scope of the disclosure. It isunderstood that the invention is not limited to the embodiments setforth herein for purposes of exemplification, but is to be limited onlyby the scope of the attached claims, including the full range ofequivalency to which each element thereof is entitled.

PARTS LIST

8 . . . magnetic transport system

10 . . . frame

12 . . . web

14 . . . reservoir

15 . . . interior portion

16 . . . magnetically polarized components

17 . . . rotation arrows

18 . . . arrows

20 . . . roller

22 . . . core

24 . . . first bonding layer

26 . . . first layer

28 . . . second bonding layer

30 . . . second layer

32 . . . tapered end

50 . . . end support member

52 . . . end support member

54 . . . shaft

56 . . . shaft

58 . . . opening

60 . . . motor

70 . . . rotor shaft

72 . . . rotation arrow

74 . . . rotation arrow

76 . . . ferromagnetic base layer

84 . . . first web bonding layer

86 . . . first web layer

88 . . . second web bonding layer

90 . . . second web layer

What is claimed is:
 1. A method for transporting magnetic objects,comprising the steps of:providing a frame; providing at least onetransport roller mounted to said frame, said roller comprising amagnetic core; a first bonding layer at least partially surrounding andbonded to said core; a first layer at least partially surrounding andbonded to said first bonding layer, said first layer comprising acorrosion resistant material; a second bonding layer at least partiallysurrounding and bonded to said first layer; a second layer at leastpartially surrounding and bonded to said second bonding layer, saidsecond layer comprising a wear and abrasion resistant material;providing a web comprising a ferromagnetic material for movement aboutsaid transport roller; providing means for rotating said transportroller so that said web moves along said roller under the influence of amagnetic coupling between said roller and said web; providing areservoir of permanent magnet objects for transport by said web; placingsaid permanent magnet objects into close magnetic proximity of said web;rotating said transport roller so as to transport said permanent magnetobjects from said reservoir to an upstream station along said web; and,removing said objects from said web.
 2. The method recited in claim 1,wherein said step of providing a reservoir includes the step of at leastpartially filling the reservoir with said objects.
 3. The method recitedin claim 2, wherein said step of providing a reservoir further includesthe step of vibrating said reservoir prior to placing the objects ontosaid web.
 4. The method recited in claim 1, wherein said step ofproviding a reservoir further includes the step of chemically etchingsaid objects prior to the step of placing said objects onto said web. 5.The method recited in claim 1, wherein said step of providing areservoir further includes the step of providing a reservoir containinga solution with magnetic particles dispersed therein for separating saidparticles from said solution.